eal: add telemetry as dependency

eal: add telemetry as dependency

This patch moves telemetry further down the build, and adds it as a
dependency for EAL. Telemetry V2 is now configured to build by default,
and the legacy support is built when the telemetry config flag is set.

Telemetry now has EAL flags, shown below:
"--telemetry" = Enables telemetry (this is default if no flags given)
"--no-telemetry" = Disables telemetry

When telemetry is enabled, it will attempt to open the new socket
version, and also the legacy support socket (this will depend on Jansson
external dependency and telemetry config flag, as before).

Signed-off-by: Ciara Power <ciara.power@intel.com>
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Keith Wiles <keith.wiles@intel.com>